An Initial Research On The Bladder Pacemaker Cells

Under physiological condition, spontaneously and regularly occurring slow waves which are propagated caudad from the dome toward the trigone, can be recorded in the bladder in vivo. These SWs are postulated arised from a pacemaker located in the vesical dome. In detrusor instability, the coordinated contraction of the whole or most part of the bladder implicates pacemaker cells existing in the bladder which produce the highest excitability. When denervated by distribution nerves being cut or nerve blockers being applied, the detrusor smooth muscle strips still show spongtaneous contraction in vitro. The phenomenon suggests the contraction is myogenic in nature and is controlled by pacemaker cells. The theoretically existing pacemaker cells of the bladder is still unknown.The pacemaker function of interstitial cells of Cajal(ICC) in the gastrointestinal tract and the similar physiological characteristics of smooth muscle in bladder and gut provide ICC as an ideal objective for the foundation of bladder pacemaker cells. KIT immunohistochemistry can identify ICC specifically. ICC-like cells which are KIT immunostaining positive and have the semblable morphology with ICC have been found in the guinea pig and human bladder. They were thought the good candidate for bladder pacemaker cells. The literatures about ICC-like cells in the bladder are few and mainly focus on the morphology research. The direct proof to testify ICC-like cells as bladder pacemaker cells is still lacking. In our research, we identified the existing of ICC-like cells in the adult guinea pig bladders firstly. Secondly, the ICC-like cells and detrusor smooth muscle cells of primary cultured were harvested by collagenase digestion of the bladder tissue.And thirdly, pactch clamp technology and whole-cell recording mode were performed on the ICC-like cells to investigate whether pacemaker currents exist in them. The results is helpful to enrich neurophysiology theory of the bladder, important for understanding of the physiology and pathology of micturition and to provide new targets...